c - 为什么写入我的文件的文本完全正常，直到最后几行，当它在 c 中循环时？

Question

我一直在用 c 编写一个小程序，正在创建的文件直到最后 150 行左右才开始获取随机字符，有时是我的程序的文件路径或其中的一部分是正确的。

注意:我使用 Mac Retina 和 Xcode 来编写和测试。

编辑:除非您想查看整个函数，否则我已将给我带来麻烦的部分放在此代码下面

int vieditor()
{
    FILE *readtext, *writetext,*testfile,*writeagain;
    char mytest[1000][81],controller = '\0',worq;;
    int x,charactersperline = 0,lines = 0,i,k;



    /* this just creates a file with 1000 lines */
    testfile = fopen("/Users/scottcarlson/Classes/CS_222/test.txt","w");
    for (i = 0; i<1010; i = i+1)
    {
    fprintf(testfile,"this is line %d \n",i);
    }
    fclose(testfile);
    /* end of file creation */

    readtext = fopen("/Users/scottcarlson/Classes/CS_222/test.txt","r");
    writetext = fopen("/Users/scottcarlson/Classes/CS_222/test1.txt","w");

    if (!readtext)
    {
        printf ("test.txt does not exist");
    }
    else
    {
        while ( ( x = fgetc( readtext ) ) != EOF )
        {
            if (charactersperline < 80 && lines < 1000)
            {
                fprintf(writetext,"%c",x);
                char ch = x;
                mytest[lines][charactersperline] = ch;
                if (lines < 20)
                {
                    printf("%s",&mytest[lines][charactersperline]);
                }
            }

            if (x != 10)
            {
                charactersperline += 1;
            }
            else
            {
                charactersperline = 0;
                lines += 1;
            }

        }
        fclose(readtext);
        fclose(writetext);


    }
    do
    {
        fseek(stdin,0,SEEK_END);
        system("stty raw -echo");
        controller = getchar();
        system("stty cooked echo");
    }
    while (controller != 58);
    scanf("%s",&worq);
    if (worq == 'w')
    {
            writeagain = fopen("/Users/scottcarlson/Classes/CS_222/test.txt","w");
            for (k = 0; k<lines; k = k+1)
            {
                    fprintf(writeagain,"%s",mytest[k]);

            }

    }
    else if (strncmp(&worq,"q!",5))
    {
        return 0;
    }


    return 0;
}

这就是整个函数，但是除非你愿意，否则你不需要看它，给我带来麻烦的部分是这里的底部

do
{
    fseek(stdin,0,SEEK_END);
    system("stty raw -echo");
    controller = getchar();
    system("stty cooked echo");
}
while (controller != 58);
scanf("%s",&worq);
if (worq == 'w')
{
        writeagain = fopen("/Users/scottcarlson/Classes/CS_222/test.txt","w");
        for (k = 0; k<lines; k = k+1)
        {
                fprintf(writeagain,"%s",mytest[k]);

        }

}
else if (strncmp(&worq,"q!",5))
{
    return 0;
}


return 0

这应该打印(覆盖)文件 test.txt，它在大约第 840 行之前都表现得很好，据我所知，这根本没有任何意义。

如果有人可以提供帮助，我将不胜感激，因为我在其他地方找不到这方面的信息。

这是文件 test.txt 开始写入随机内容的部分。

this is line 838 
this is line 839 
∆ø_ˇthis is line 840 
¿_ˇthis is line 841 
this is line 842 
ˇthis is line 843 
this is line 844 
this is line 845 
this is line 846 
this is line 847 
’ø_ˇthis is line 848 
–è7zthis is line 849 
_ˇthis is line 850 
ˇthis is line 851 
this is line 852 
this is line 853 
this is line 854 
Ä◊ø_ˇthis is line 855 
◊ø_ˇthis is line 856 
ïˇthis is line 857 
_ˇthis is line 858 
this is line 859 
this is line 860 
this is line 861 
this is line 862 
∞Ãø_ˇthis is line 863 
Ãø_ˇthis is line 864 
éìˇthis is line 865 
this is line 866 
ˇthis is line 867 
/lithis is line 868 
this is line 869 
this is line 870 
p¶√_ˇthis is line 871 
de/DerivedData/Project_5.c-akilnssybkcyvuetuwkrqlyxxtie/Build/Pthis is line 872 
ystem_pthread.dylibthis is line 872 
ystem_pthread.dylibthis is line 873 
this is line 874 
ˇthis is line 875 
this is line 876 
this is line 877 
this is line 878 
this is line 879 
.c-akilnssythis is line 880 
this is line 881 
_ˇthis is line 882 

Answer 1

您在 mytest 中没有以空终止行。 fprintf 期望在使用 %s 打印时在字符串末尾看到 '\0'。

当您逐个字符复制到 mytest 中时，您需要输入代码以在每行末尾添加 '\0'，或者您可以在开头将整个数组初始化为 '\0'。最简单(但不是最有效)的方法是在每次添加字符后添加“\0”。

mytest[lines][charactersperline] = ch;
mytest[lines][charactersperline+1] = '\0';

当您开始新行时，您还必须在行的开头添加一个零字节，因为您的循环可能不会继续将任何内容放入该行中。

请注意，如果您的文件中没有任何内容，或者您​​的文件不以“\n”结尾，那么您也会遇到问题，因为您不会增加行数行

还有

printf("%s",&mytest[lines][charactersperline]);

应该是 %c 而不是 %s，因为您正在打印单个字符。